Mechanism for converting rotary into reciprocatory motion



R. GOLDSCHMIDTa IIIIECHANISIVI FOB CONVERTING ROTARY INTO RECIPROCATORYMOTION.

APPLICATION FILED SEPT.20, 1921.

LMQQJIQID Fab embed. 2119 1922,

FIG.

2 b'HhETS-SHEET 1-- R. GOLDSCHMIDT MECHANISM FOR CONVERTING ROTARY INTORECIPROCATORY MOTION,

APPLICATION FILED sEPT.20.1021. lAlQGlQL Patented Mar. 2L 1922..

2 SHlzETSSHEET 2- UNITED STATES PATENT OFFICE.

I RUDOLF GQLDSCHMIDT, OF BERLIN, GERMANY, ASSIGNOR TO DET TEKNISKEFOBSGS- AKTIESELSKAJB, OF ORDRUP GHARLOTTENLUND, DENMARK, A COMPANY OFDEN- MARK.

MECEANISM FOR CONVERTING ROTARY INTO RECIPROCATORY MOTION.

Patented Mar. 21, 1922.

Application flied September 20, 1921. Serial No. 501,987.

' a citizen of Germany, and a resident of Berlin, Germany, have inventedcertain new and useful Mechanism for Converting Rotary intoReciprocatory Motion, of which the following is a specification.

This invention relates to improvements in mechanism for convertingrotary into reciprocatory motion, applicable to reciprocatory orpercussive tools or other reciproc'atory apparatus.

According to the present invention, the member which is reciprocated bymeans of a centrifugal Weight or Weights or the journal of said weightsis capable of movement at right angles to the path of reciprocation orspirally and a spring or othermeans is provided for yielding restrainingthis movement.

The object of the present improvements is to mitigate or eliminate thevibrations due to the lateral forces set up in the reciprocatory memberby the rotation of the centrifugal weights and also to reduce theconsequent friction on the lateral guides of the reciprocatory member.

The invention is hereinafter described with reference to theaccompanying explanatory drawings whereon:

Fig. 1 is a sectional view of a percussive hand tool in its preferredform.

Fig. 2 is a diagrammatic viewillustrating a modified form of myinvention.

Figs. 3 and 4: are side and cross-sectional views respectively ofmechanism illustrating how the lateral forces are set up.

Fig. 5 is a longitudinal section and Fig. (i an end view showing theapplication of my improvements to such mechanism.

Fig. 7 is a plan view (partly in section) of the mechanism shown in Fig.5.

Referring firstly to Fig. 2 of the drawings, the mechanism shown thereinis of the type described in my prior patent specification (Serial No.436206) and comprises a member a having a journal 0 for the arm 8 of acentrifugal weight 0 and capable of sliding between guides f and springbuffers 01 and e. In this arrangement, the member is reciprocated b aforce H and subject to a lateral force which gives rise to friction onthe guides f and vibration of the mechanism. In order to overcome thisfriction and vibration, the journal 0 may be carried by a blocka movablein relation to the member a in a direction at right angles to the pathof reciprocation. The-force V is then absorbed in displacing the block atransversely and the movement of the latter may be limited by springs g.

Figs. 3 and at illustrate an arrangement similar to that of Fig. 2 of myaforesaid prior patent specification in which, although the twocentrifugal weights 0' and 0 are so arranged that the forces V arebalanced, a turning moment M is set up ?which changes in direction atevery half revolution. In order to minimize the effect of this turningmoment, the member a may be so mounted that it can follow the turningmoment M by turning on its own axis. In this manner unilateral pressureon the guides f is over-1- come. The turning movement of the memf ber ais preferably yieldingly restrained'by a spring.

Such an arrangement is illustrated in Figs. 5, 6, and 7 wherein themember a is supported by spindles Z) and b the spindle Z) sliding in abearing f and the spindle 6 being keyed to a bush h which is slidableand rotatable in a bearing 7, the bush h projecting through the bearingso as to receive a gear wheel r slidably keyed thereto by means of a keyr and key way r in the bush h. The bush It carries a bevel wheel 7:;gearing with a pair of bevel wheels $3 each rigidly connected to the arm8 of the centrifugal weights 0 and 0 and rotatable on a crosspin p.Between the bearing f and the crosspin p is fitted a helical spring afixed at its end to the bearing f at n and at its other end at n? to thecross-pin p.

The member a is thus capable not only of reciprocation under theinfluence of the rotating weights 0 and 0 but also of rotation asindicated by the double arrows I in Fig. 6 under the influence of theturning moments. These oscillations are resiliently absorbed or reducedby the spring n which also serves to eliminate any slight variations inthe angular velocity of the bush h, due to irregularity in the powersupply. Also, when the mechanism is applied to a hammer or ram, a pauseoccurs in the movement of the member a during the impact, this pausereacting on the mechanism. The reaction in such case is also absorbed bythe sprmg n,

whilst the gear wheels 70 roll upon the ear] of which is mounted a gearwheel 11 meshing with a gear wheel 12. The wheel 12 is loose upon ashaft 13 journalled in the casing and drives the shaft 13 through a coilspring 14 which thus absorbs irregularities due to variation of theelectric power supply. The shaft 13 extends into a hollow bush 15 whichis splined thereon and which carries a pinion 16 and an extension 17.The latter supports a bush 18 and a pair of arms or tubes 19 on whichare rotatably mounted a pair of eccentric weights 20 carrying gear teeth21 which mesh with the pinion 16. The outer extremities of the arms 19support rings or eyes 22 formed upon or carried by a rlng or collar 23which is a loose fit in the casing'8. The collar 23 is shown cut away toallow for the rotation of the weights 20. A spring 24 is interposedbetween the collar 23 and a web 25 which extends across the casing andsupports the journal of the shaft 13. The spring 24 is fixed at one endto the web 25 and at the other end to the collar 23. Centered at one endby the extension 17 and slidably supported at its other end in a sleeve26 is a tup or hammer 27 adapted to strike againsta button 28 in thecentre of a flexible diaphragm 29. The sleeve 26 has a disc-shapedextension 26* which serves to clamp the diaphragm 29 upon a tool holder30 which encases a spring 31 hearing against the button 28. The toolholder 30 has a central hollow guide 32 for the tool 33. The guide 32also serves to center a sleeve or bush 34 carried by the button 28. Anose 35 having a threaded portion 36 screwed into the head of the toolholder 30 serves as an abutment for-a shoulder 37 on the tool 33, sothat by adjustment of the nose 35, the distance between the inner end ofthe tool 33 and the button 28 can be varied, thus varying the length ofstroke of the tool. The tool holder 30 is shown threaded into the end ofthe casing 8 at 38, so that it may be removed together with thediaphragm 29 and sleeve 26, whereupon the reciprocatory mechanism isreadily accessible.

The hand grip 9 is shown fitted with a prlng thumb piece 39, whosespring 40 ugal weight pivoted presses against a slide block 41 carryinga plug or pin 42, which when inwardly pressed, establishes electricalcontact between two spring contacts 43 and thus closes the motorcircuit.

Claims- 1. Mechanism for converting rotary into reciprocatory motion comrising a recipio catory mem er, a journa carried thereby and movable ina direction at right angles to the path of reciprocation, a centrifugalweight mounted on said journal, means for rotating said weight and meanswhereby said journal is ieldingly restrained in its movement at rig tangles to the path of reciprocation.

2. Mechanism for converting rotary into reciprocatory motion, comprisinga reciprocatory member capable of spiral motion around its axis ofreciprocation, a centrifthereto and means for yieldingly restrainingsaid spiral motion.

3. Mechanism as specified in claim 2 in Y which the means forrestraining spiral motion consists of a helical spring fixed at oneendand secured at its other end to the reciprocatory member.

4. In a reciprocatory tool, a'reciprocatory tup, a centrifugal Weightpivotally mounted on the tup, means for rotating said weight, a casingfor the tup and a spring connected at one end to the casing and at theother end. to the tup.

5. In a reciprocatory tool, a casing, a drivlug shaft journalled in saidcasing, means for driving said shaft, a gear wheel splined on saidshaft, arms journalled on an extension of said gear wheel, eccentricweights rotatable on said arms and geared to said gear wheel, a tupsupported by said arms and slidable in a journal in sai casing and meansfor yieldingly restraining spiral motion of the parts about saidextension.

6. A tool as specified in claim 5 in which the restraining meanscomprises a collar said arms and a spiral spring fixed at one end tosaid collar and at the other end to said casing.

7. A tool as specified in claim 5 having a nflotgr within the casing,for the driving s a;

8. A tool as specified in claim 5 having an electric motor within thecasing, a handle for the casing and a push switch on the handle forcontrolling said motor.

9. A tool as specified in claim 5 having a tool socket on the end of thecasing, a flexible diaphragm between said tool socket and the tup and aspring for pressing said diaphragm towards the tup.

In testimony whereof I hereunto ailix my signature.

RUDOLF GOLDSCHMIDT.

